Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 222 insertions, 0 deletions

diff --git a/net/ipv4/gre_demux.c b/net/ipv4/gre_demux.c
new file mode 100644
index 000000000..9376b30cf
--- /dev/null
+++ b/net/ipv4/gre_demux.c
@@ -0,0 +1,222 @@
+/*
+ *	GRE over IPv4 demultiplexer driver
+ *
+ *	Authors: Dmitry Kozlov (xeb@mail.ru)
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/if.h>
+#include <linux/icmp.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/netdevice.h>
+#include <linux/if_tunnel.h>
+#include <linux/spinlock.h>
+#include <net/protocol.h>
+#include <net/gre.h>
+#include <net/erspan.h>
+
+#include <net/icmp.h>
+#include <net/route.h>
+#include <net/xfrm.h>
+
+static const struct gre_protocol __rcu *gre_proto[GREPROTO_MAX] __read_mostly;
+
+int gre_add_protocol(const struct gre_protocol *proto, u8 version)
+{
+	if (version >= GREPROTO_MAX)
+		return -EINVAL;
+
+	return (cmpxchg((const struct gre_protocol **)&gre_proto[version], NULL, proto) == NULL) ?
+		0 : -EBUSY;
+}
+EXPORT_SYMBOL_GPL(gre_add_protocol);
+
+int gre_del_protocol(const struct gre_protocol *proto, u8 version)
+{
+	int ret;
+
+	if (version >= GREPROTO_MAX)
+		return -EINVAL;
+
+	ret = (cmpxchg((const struct gre_protocol **)&gre_proto[version], proto, NULL) == proto) ?
+		0 : -EBUSY;
+
+	if (ret)
+		return ret;
+
+	synchronize_rcu();
+	return 0;
+}
+EXPORT_SYMBOL_GPL(gre_del_protocol);
+
+/* Fills in tpi and returns header length to be pulled.
+ * Note that caller must use pskb_may_pull() before pulling GRE header.
+ */
+int gre_parse_header(struct sk_buff *skb, struct tnl_ptk_info *tpi,
+		     bool *csum_err, __be16 proto, int nhs)
+{
+	const struct gre_base_hdr *greh;
+	__be32 *options;
+	int hdr_len;
+
+	if (unlikely(!pskb_may_pull(skb, nhs + sizeof(struct gre_base_hdr))))
+		return -EINVAL;
+
+	greh = (struct gre_base_hdr *)(skb->data + nhs);
+	if (unlikely(greh->flags & (GRE_VERSION | GRE_ROUTING)))
+		return -EINVAL;
+
+	tpi->flags = gre_flags_to_tnl_flags(greh->flags);
+	hdr_len = gre_calc_hlen(tpi->flags);
+
+	if (!pskb_may_pull(skb, nhs + hdr_len))
+		return -EINVAL;
+
+	greh = (struct gre_base_hdr *)(skb->data + nhs);
+	tpi->proto = greh->protocol;
+
+	options = (__be32 *)(greh + 1);
+	if (greh->flags & GRE_CSUM) {
+		if (!skb_checksum_simple_validate(skb)) {
+			skb_checksum_try_convert(skb, IPPROTO_GRE, 0,
+						 null_compute_pseudo);
+		} else if (csum_err) {
+			*csum_err = true;
+			return -EINVAL;
+		}
+
+		options++;
+	}
+
+	if (greh->flags & GRE_KEY) {
+		tpi->key = *options;
+		options++;
+	} else {
+		tpi->key = 0;
+	}
+	if (unlikely(greh->flags & GRE_SEQ)) {
+		tpi->seq = *options;
+		options++;
+	} else {
+		tpi->seq = 0;
+	}
+	/* WCCP version 1 and 2 protocol decoding.
+	 * - Change protocol to IPv4/IPv6
+	 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
+	 */
+	if (greh->flags == 0 && tpi->proto == htons(ETH_P_WCCP)) {
+		u8 _val, *val;
+
+		val = skb_header_pointer(skb, nhs + hdr_len,
+					 sizeof(_val), &_val);
+		if (!val)
+			return -EINVAL;
+		tpi->proto = proto;
+		if ((*val & 0xF0) != 0x40)
+			hdr_len += 4;
+	}
+	tpi->hdr_len = hdr_len;
+
+	/* ERSPAN ver 1 and 2 protocol sets GRE key field
+	 * to 0 and sets the configured key in the
+	 * inner erspan header field
+	 */
+	if ((greh->protocol == htons(ETH_P_ERSPAN) && hdr_len != 4) ||
+	    greh->protocol == htons(ETH_P_ERSPAN2)) {
+		struct erspan_base_hdr *ershdr;
+
+		if (!pskb_may_pull(skb, nhs + hdr_len + sizeof(*ershdr)))
+			return -EINVAL;
+
+		ershdr = (struct erspan_base_hdr *)(skb->data + nhs + hdr_len);
+		tpi->key = cpu_to_be32(get_session_id(ershdr));
+	}
+
+	return hdr_len;
+}
+EXPORT_SYMBOL(gre_parse_header);
+
+static int gre_rcv(struct sk_buff *skb)
+{
+	const struct gre_protocol *proto;
+	u8 ver;
+	int ret;
+
+	if (!pskb_may_pull(skb, 12))
+		goto drop;
+
+	ver = skb->data[1]&0x7f;
+	if (ver >= GREPROTO_MAX)
+		goto drop;
+
+	rcu_read_lock();
+	proto = rcu_dereference(gre_proto[ver]);
+	if (!proto || !proto->handler)
+		goto drop_unlock;
+	ret = proto->handler(skb);
+	rcu_read_unlock();
+	return ret;
+
+drop_unlock:
+	rcu_read_unlock();
+drop:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+static void gre_err(struct sk_buff *skb, u32 info)
+{
+	const struct gre_protocol *proto;
+	const struct iphdr *iph = (const struct iphdr *)skb->data;
+	u8 ver = skb->data[(iph->ihl<<2) + 1]&0x7f;
+
+	if (ver >= GREPROTO_MAX)
+		return;
+
+	rcu_read_lock();
+	proto = rcu_dereference(gre_proto[ver]);
+	if (proto && proto->err_handler)
+		proto->err_handler(skb, info);
+	rcu_read_unlock();
+}
+
+static const struct net_protocol net_gre_protocol = {
+	.handler     = gre_rcv,
+	.err_handler = gre_err,
+	.netns_ok    = 1,
+};
+
+static int __init gre_init(void)
+{
+	pr_info("GRE over IPv4 demultiplexor driver\n");
+
+	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
+		pr_err("can't add protocol\n");
+		return -EAGAIN;
+	}
+	return 0;
+}
+
+static void __exit gre_exit(void)
+{
+	inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
+}
+
+module_init(gre_init);
+module_exit(gre_exit);
+
+MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver");
+MODULE_AUTHOR("D. Kozlov (xeb@mail.ru)");
+MODULE_LICENSE("GPL");